The present invention relates to a method for supplying current from an inverter power supply via relays to successive sections of the stator of a linear motor.
In a linear electromagnetic drive composed of a long stator and a runner mounted on a vehicle, the long stator is customarily subdivided into several stator sections. The "runner" corresponds to the rotor of a rotary motor. For reasons of economy, energy from a constant frequency inverter power supply is conveyed only to those sections on which vehicles are actually located at any given time. In the past, it has been customary to employ several inverter power supplies to feed successive stator sections and to switch the respective sections in and out when the vehicle was getting ready to enter a particular section or had just left it. However, this method requires a plurality of inverter power supplies and increased costs for cabling. Moreover, Federal Republic of Germany Offenlegungsschrift (published but unexamined patent application) 3,317,964.7 discloses the supplying of several successive stator sections by means of a single constant frequency inverter power supply in such a manner that an individual section under load is switched on or off by way of hybrid relays when the vehicle has just entered the section or left it, respectively. The drawback here is the high cost for the complicated hybrid relays.